A circuit arrangement of this type--connected to a direct voltage supply--is provided in order, by means of switching devices appertaining thereto to switch electrical consumers cooperating therewith on and off in a power-free manner. Only one signal current is directed via the switching devices by means of which power drivers, for example, relays or power semi-conductors, allocated to the electrical consumers can be actuated. In order, in the case of a plurality of switching devices allocated to a circuit arrangement, to avoid connecting each switching device to its power driver by means of its own electric line it is known to provide them with a respective resistor. The resistors differ in their resistance value so that control signals are imparted to evaluation electronics allocated to the power drivers of the electrical consumers and these control signals move to a different level in the manner of a voltage encoding.
A problem in this principle of operation which is in itself very reliable is that in the case of a multiplicity of switching devices the voltage level appertaining to the switching devices or the currents resulting therefrom no longer differ from each other in their gradation in such a way that, in particular, in the case of a plurality of switching devices operating simultaneously, a reliable detection and allocation of these switching devices or of an individual switching device is ensured by the evaluation electronics.